Culture
In St. Louis, paper birch is best grown in medium to wet, well-drained sandy or rocky loams in part shade. It is best sited in a northern or eastern exposure that receives some afternoon shade. It needs consistently moist soils. Consider using soaker hoses and bark mulches to keep the root zones cool and moist. It needs little pruning, but if necessary, prune during the dormant season. Avoid pruning in spring when the sap is running. Performs best in cool northern climates where summer temperatures rarely exceed 75 degrees F. and where root zones are generally covered with snow throughout the winter.
Noteworthy Characteristics
Betula papyrifera, commonly called paper birch or canoe birch, is primarily native to the cold climates of Canada and Alaska (USDA Zones 1-3), with its range dipping down into a few of the northern U.S. states (USDA Zones 4-5A) and further south in the mountains (to Colorado in the Rockies and to North Carolina in the Appalachians). This tree is noted for its white bark, which exfoliates in papery strips to reveal an orange-brown inner bark. Mature trees develop black markings on the white bark. Single trunk trees grow to 50-70’ tall with an oval rounded crown. Multi-trunked trees grow shorter with a more irregular crown. Ovate, irregularly toothed, dark green leaves (to 4” long). Quality clear yellow fall color. Tiny monoecious flowers appear in early spring in separate catkins on the same tree: yellowish-brown male flowers in drooping catkins (to 4” long) and greenish female flowers in smaller, upright catkins (to 1 1/4” long). Female flowers are followed by drooping cone-like fruits containing numerous small winged seeds that typically mature in late summer. The use of the bark for making birch bark canoes is well known.
Genus name is the Latin name for birch.
Specific epithet means paper-bearing.
Problems
This species of birch grows poorly and is generally short-lived in the St. Louis climate. It thrives in cool northern summers, but does poorly in the heat and humidity of St. Louis summers. Weakened birches become vulnerable to the bronze birch borer which, in the St. Louis area, typically infects and kills trees that are stressed by summer heat and humidity. Although paper birches have some susceptibility to aphids, leaf miner, birch skeletonizer and dieback, these problems are somewhat minor in comparison to the borer.
Uses
In cool northern climates, paper birch is an excellent landscape tree that mixes well with evergreens and produces good fall color. It is not recommended for the St. Louis climate. River birch (see Betula nigra) is a better selection for St. Louis.